hi guys, im lookin at an 03 sts that comes with a factory touchscreen nav/dvd with 6 disc changer. i was messing with it today during the testdrive but didnt have all the time in the world to figure it out. i found that when watching a movie as soon as i put it in gear it shut off....now, im hearing that its possible to fix this; if so, somebody please reassure me of this before i buy it. also, how easy is it to expand on the existing system? i would replace amps and speakers preferably. i'd just much rather leave the factory head unit in place. anybody who knows about this system please help, i might buy this car and i dont want to buy it if it will be more of a headache than a luxury/convenience. thanks